Attention is being focused on carbon materials with a graphene structure because they have high Young's modulus and high electrical conductivity. Compounding such a carbon material with a graphene structure into a synthetic resin enables reinforcement of a product made of the synthetic resin and impartment of electrical conductivity to the product. In particular, a graphene sheet, a carbon nanotube, flaked-graphite or the like has a nanoscale size and a large specific surface area. Therefore, such a carbon material is believed to exhibit a high reinforcing effect when it is compounded into resin.
Generally, in order that the resultant compound is more effective as a composite material, it is preferred that the carbon material be uniformly dispersed in the matrix resin. Patent Literature 1 below discloses a method in which a good solvent for a thermoplastic resin and a carbon material is used to obtain a uniform dispersion state. This method provides a resin composite material having a uniform dispersion state, provided a common solvent for the thermoplastic resin and the carbon material.